Process for discharging dyeings on wool



Patented Dec. 10, 1935 UNITED STATES PROCESS FOR DISCHARGING DYEINGS ON WOOL Robert Haller, Riehen, near Basel, Switzerland, assignor to firm Society of Chemical Industry in Basle, Basel, Switzerland No Drawing. Application October 16, 1934, Serial No. 748,533. In Switzerland October 21, 1933 4 Claims.

It is known that many dyestufis can be discharged on wool with the aid of sulfoxylates. Among the decomposition products of the sulfoxylates which are produced in the operation are 5 sulfides which attack the wool very strongly so that the discharged parts easily become tender.

This invention relates to a process in which this difiiculty is avoided or minimized and consists in adding to the discharge paste a compound which, during the steaming, reacts with sulfides. Such compounds are, for example, those containing a. halogen atom capable of exchange such as salts of chloroacetic acids or other halogen fatty acids. Such acids are for instance mixtures of monodiand trichloroacetic acid which are formed in the chlorination of acetic acid. Further also such acids as bromoacetic acid, chloroproprionic acid, etc.

The usual procedure is followed, namely the printing of the discharge paste, steaming and washing. It has been found that the purity of the discharge printing is greatly enhanced if the discharge paste is mixed with a hygroscopic agent such as glycerine, thiodiglycol, urea or a mixture of such compounds. Also zinc oxide or lithopone may be added to the discharge paste.

Subject matter of the present invention are further also the compositions of matter which are used for carrying out the new discharge process. These are discharge pastes for wool printing containing, besides the usual thickenings and other additions and a sulfoxylate, one of the above named substances which react with sulfides during the steaming operation.

The following examples illustrate the invention, the parts being by weight:-

Example 1 A discharge paste is prepared by introducing 25 parts of a mixture consisting of 70 per cent of sodium sulfoxylate and 30 per cent of zinc oxide, 10 parts of glycerine, 10 parts of sodium monochloracetate and 10 parts of urea into 50 parts of a British gum thickening (1:1).

The wool fabric dye with a dyestuff capable of discharge is printed with this discharge paste and then steamed with moist steam in the rapid steamer for 5-6 minutes whereby the discharge becomes effective at the printed parts. The discharge fabric is thoroughly washed. Whereas the discharge paste containing no sodium monochloracetate gives rise to a strong weakening of the fibres of the discharge parts a paste made as described in the present example exerts far less weakening effect on the fibre.

Example 2 The dyeing capable of discharge is printed with a discharge paste Without the addition of urea prescribed in Example 1 and in the manner described in Example 1.

Example 3 Chlorinated wool which has been dyed with a dyeing capable of discharge is printed with the 10 following discharge pastezegrams of British gum (1:1), 25 grams of a. mixture consisting of '70 parts of sodium sulfoxylate and 30 parts of zinc oxide, 15 grams of thio-diglycol and 10 grams of a mixture of the r alkali salts of the various chloracetic acids are thoroughly mixed. The print is steamed in a Mather-Flatt apparatus for 4-5 minutes, washed in warm water and lightly soaped at 50 C.

Example 4 Woollen fabric dyed with Benzyl Bordeaux B (compare Schultz Farbstoiitabellen, 7th edition, No. 120) is printed with a discharge paste consisting of 300 grams of gum arabic (1:1), 350 grams of a mixture of parts of soduim sulfoxylate and 30 parts of zinc oxide, grams of glycerine and grams of titanium white (1:1), 70 grams of sodium monochloracetate and 30 grams of Quinoline yellow (compare Schultz Fargstofftabellen, 6th edition, No. 613) and '70 grams of water. The goods are steamed in the rapid steamer for 5 minutes and washed. There is obtained a yellow discharge efiect on'a red ground.

What I claim is:-

1. A process of discharging dyeings on wool by means of sulfoxylates, consisting in using a discharge paste containing besides the thickening and the usual additions the salt of an 40 aliphatic halogen-acetic acid.

2. A process of discharging dyeings on wool by means of sulfoxylates, consisting in using a discharge paste containing besides the thickening and the usual additions a salt of a halogen-acetic 45 acid.

3. A process of discharging dyeings on wool by means of sulfoxylates, consisting in using a discharge paste containing besides the thickening and the usual additions a salt of a chloro-acetic 50 acid.

4. A process of discharging dyeings on wool by means of sulfoxylates, consisting in using a discharge paste containing besides the thickening and the usual additions a salt of monochloro- 55 acetic acid.

ROBERT HALLER. 

